I am puzzled also. Even some newly commisioned ILS approaches require
ADFs to locate the outermarker for hold. We had one at a local airport
and I wrote to OK City and they agreed that they rushed the design. I
commented that the hold point could easily be located by the localizer,
the feeder route from the nearby VOR, and the marker beacon. However,
when the genius redesigned the procedure they had us flying 40 miles out
of the way to hold, not evening using the feeder VOR, but another one. I
withdrew my letter. They left the procedure with the ADF required. I
have noticed a couple of other approaches in the area that had changes
adding the ADF requirement. According to the designers, this provides a
lesser workload on the pilot flying the missed approach.

Greg Farris wrote:

I came across the same question recently, as I happened in one day to see
three Cessna panels with full-on Garmin panels but no ADF. So I did an
informal look at Trade-A-Plane, which confirms the tendancy. I get the
impression that a good 50% of those overhauling their panel chose to
chuck the ADF, and the proportion of new panels delivered (pre-G1000)
without ADF is similar, if not higher.

This puzzles me, because of the number of approaches still published with
ADF requirement - why spend thousands to have the latest and greatest,
if it's to restrict your use of so many approaches? I'm aware that many
instrument students prefer not to have it, because if it's there they
will be asked to demonstrate proficiency with it on the checkride - yet
I fail to understand just why this requirement strikes terror in peoples'
hearts!

I am also saddened to see the DME go, which seems to be part of the same
trend, though I do accept the argument that with a G430 and a G530
stacked in the panel you're hardly getting any more information from a
DME!

As for RMI - sure it's great to have a VOR/NDB RMI for your DME arcs etc,
but how many piston singles actually have this? I see them in KingAirs,
but not in 172's.

GF